Boosting device

ABSTRACT

A boosting device is provided with a drive unit which is driven under the action of energization, and a boosting mechanism which is connected to the drive unit and which boosts and outputs a pressurized fluid. The boosting mechanism comprises a rotating body which is connected to a drive shaft of a drive source and includes a slope portion, and four pistons opposing the rotating body and disposed moveably in an axial direction. The pistons are sequentially and continuously pushed in the axial direction by means of the slope portion of the rotating body, whereby the pressurized fluid is compressed and boosted in a boosting chamber. The pressurized fluid that has been boosted in the boosting chamber is discharged out of an output port through a discharge passageway when an exhaust check valve is opened.

TECHNICAL FIELD

The present invention relates to a boosting device that is capable of increasing the pressure of a supplied pressure fluid and outputting the boosted fluid.

BACKGROUND ART

Boosting devices are conventionally known which compress pressure fluid such as gas, air, etc. to increase the pressure of the fluid and output the boosted fluid. For example, the boosting device disclosed in International Publication No. WO 2013/183586 includes a rotating shaft that is rotatably supported in a housing and a swash plate attached to the rotating shaft such that the swash plate is inclined at a given angle with respect to the axial direction. Further, pistons that can stroke within the housing are engaged with peripheral portions of the swash plate. Then, the rotating shaft is rotated to rotate the swash plate, and the rotating movement presses the pistons to cause the pistons to reciprocate in the axial direction, whereby the pressure fluid in the housing is compressed by the pistons and delivered to the outside.

SUMMARY OF INVENTION

Recently, compacter boosting devices are demanded because space saving is desired when installing boosting devices on production lines etc.

A general object of the present invention is to provide a boosting device that can achieve size reduction and weight reduction with a simple structure.

The present invention is directed to a boosting device that includes a body having a supply port and an output port and that is configured to increase the pressure of a pressure fluid supplied from the supply port and output the boosted pressure fluid from the output port. The boosting device includes:

a driving source that is provided in the body and that is rotationally driven under an action of energization;

a rotating body coupled to a rotating shaft of the driving source and having a slope that is inclined with respect to an axis line of the rotating shaft; and

a plurality of pistons disposed to be movable in an axial direction with respect to boosting chambers in the body and each having an end that abuts on the slope,

wherein the plurality of pistons are sequentially urged in the axial direction by the slope under an action of rotation of the rotating body, so as to compress and boost the pressure fluid in the boosting chambers.

According to the present invention, the body of the boosting device includes the driving source that is rotationally driven under the action of energization, and the rotating body having the slope inclined with respect to the axis line of the rotating shaft of the driving source is coupled to the rotating shaft. The plurality of pistons are disposed in the boosting chambers in the body so as to be movable in the axial direction, and their ends abut on the slope of the rotating body.

Then, the slope sequentially urges the plurality of pistons in the axial direction as the rotating body rotates under the driving action by the driving source, and the pressure fluid is compressed and boosted by the pistons in the boosting chambers and discharged outside from the output port.

As a result, by employing a configuration in which a plurality of pistons are provided in the body and moved continuously in the axial direction by the slope of the rotating body, it is possible to compress and boost the pressure fluid with a simple structure and to thereby achieve size reduction and weight reduction of the boosting device.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating the external appearance of a boosting device according to an embodiment of the present invention;

FIG. 2 is an exploded perspective view of the boosting device shown in FIG. 1;

FIG. 3 is the cross section taken along line III-III in FIG. 1;

FIG. 4 is the cross section taken along line IV-IV in FIG. 1;

FIG. 5 is the cross section taken along line V-V in FIG. 3;

FIG. 6 is the cross section taken along line VI-VI in FIG. 3;

FIG. 7 is the cross section taken along line VII-VII in FIG. 3;

FIG. 8 is the cross section taken along line VIII-VIII in FIG. 3; and

FIG. 9 is the cross section taken along line IX-IX in FIG. 3.

DESCRIPTION OF EMBODIMENTS

As shown in FIGS. 1 to 9, the boosting device 10 includes a driving unit 12 and a boosting mechanism 14 that is coupled to the driving unit 12 and that is capable of increasing the pressure of a pressure fluid and outputting it to the outside. The driving unit 12 and the boosting mechanism 14 are disposed in a straight line along the axial direction (the direction shown by arrow A, B).

The driving unit 12 includes, for example, a casing (body) 16 having a rectangular cross section and a driving source 18 accommodated in the casing 16. The casing 16 is shaped like a bottomed tube having its one end closed (arrow A direction). The other end (arrow B direction) of the casing 16 on the boosting mechanism 14 side is opened and has four threaded holes 20 formed therethrough at its four corners along the axial direction (arrow A, B direction). Coupling bolts 42 (described later) are inserted and engaged therein.

Further, a control unit 22 (see FIGS. 1 and 2) for controlling driving of the driving source 18 (described below) is provided at one end of the casing 16.

The driving source 18 is a motor that is rotationally driven under the action of current passage, for example. The driving source 18 is accommodated in the casing 16 along the axial direction (arrow A, B direction), with its driving shaft 24 disposed on the boosting mechanism 14 side (in arrow B direction) and inserted in a first housing 26 of the boosting mechanism 14 (described below).

The boosting mechanism 14 includes first and second housings (body) 26, 28, a rotating body 30 accommodated in the first housing 26, four pistons 32 a to 32 d accommodated in the second housing 28 in such a manner that they can move in the axial direction, four pairs of intake check valves (first switching valves) 34 and exhaust check valves (second switching valves) 36 that open and close as the pistons 32 a to 32 d move, and a cover member (body) 38 that closes an end of the second housing 28.

Like the casing 16, the first and second housings 26, 28 have a rectangular cross section, for example. The first housing 26 is coupled to the other end of the casing 16 of the driving unit 12, and the second housing 28 is coupled to the other end of the first housing 26. The first and second housings 26, 28 each have through holes 40 a, 40 b formed at their four corners, and the coupling bolts 42 engaging in the threaded holes 20 of the casing 16 pass therethrough.

In the first housing 26, a space 44 having a circular cross section is formed in a center portion thereof, so as to accommodate the rotating body 30 and pistons 32 a to 32 d. The space 44 communicates with the outside of the first housing 26 through an outside-air port 46.

The second housing 28 includes four boosting chambers 48 in which the pistons 32 a to 32 d are accommodated. The boosting chambers 48 are disposed on the same circumference having a given diameter around the center of the second housing 28, and separated at equal intervals from each other along the circumferential direction. The boosting chambers 48 have a circular cross section and extend through along the axial direction (arrow A, B direction). In other words, as shown in FIG. 5, the boosting chambers 48 are arranged at intervals of 90° from each other, seen from the axial direction of the second housing 28.

Further, a rod cover 50 is provided at one end of each boosting chamber 48 on the first housing 26 side (arrow A direction) in order to movably support the piston 32 a to 32 d.

The second housing 28 has communicating passages 52 a, 52 b formed in a position between its one end and the other end, in order to allow the boosting chambers 48 to communicate with each other. Two communicating passages 52 a, 52 b are formed to extend in a direction perpendicular to the axis line of the second housing 28. As shown in FIG. 5, one communicating passage 52 a extending in a vertical direction and the other communicating passage 52 b extending in a horizontal direction intersect each other in a center of the second housing 28 to form substantially a cross shape. Each of the two communicating passages 52 a, 52 b allows diagonally disposed two of the boosting chambers 48 to communicate with each other. One end of each of the two communicating passages 52 a, 52 b extends to the outside of the second housing 28 and communicates with the outside.

As shown in FIGS. 6 and 7, in the second housing 28, for each of the boosting chambers 48, a pair of first and second valve chambers 54, 56 are formed to face the boosting chamber 48 at the other end of the second housing 28 on the cover member 38 side (arrow B direction).

The first and second valve chambers 54, 56 of each pair are arranged in parallel to each other with the axis line of the boosting chamber 48 interposed therebetween, and they extend along the axial direction (arrow A, B direction) to reach that other end of the second housing 28 and to communicate with the boosting chamber 48. The first valve chamber 54 accommodates an intake check valve 34 described later, and the second valve chamber 56 accommodates an exhaust check valve 36 described later.

A first plug 60 having a communicating hole 58 is fitted in the other end of the first valve chamber 54, so that the first valve chamber 54 communicates with supply passages 98 a, 98 b of the cover member 38 (described later) through the communicating hole 58. A second plug 62 is fitted in the second valve chamber 56 to close the second valve chamber 56.

An output port 64, from which the pressure fluid boosted in the boosting mechanism 14 is discharged, is formed in the vicinity of the other end of the second housing 28. The output port 64 is opened in an external surface of the second housing 28, and piping (not shown) is connected to the output port 64. The output port 64 communicates with two discharge passages 66 a, 66 b extending in a direction orthogonal to the axis line of the second housing 28.

As shown in FIG. 8, one discharge passage 66 a extending in a vertical direction and the other discharge passage 66 b extending in a horizontal direction intersect each other to form substantially a cross shape. The discharge passages 66 a, 66 b communicate with the four second valve chambers 56, respectively. In other words, the two discharge passages 66 a, 66 b communicate with each other, and both ends of each of the discharge passages 66 a, 66 b communicate respectively with the second valve chambers 56, so that the four second valve chambers 56 communicate with each other. Thus, the pressure fluid, boosted in the second valve chambers 56, flows to the output port 64 through the discharge passages 66 a, 66 b.

As shown in FIGS. 2 to 4, the rotating body 30 has a circular cross section, for example. One end of the rotating body 30 forms a flat plane extending orthogonal to the axis line. The driving shaft 24 of the driving source 18 is coupled to the flat plane in the center portion thereof. The other end of the rotating body 30 forms a slope 68 being a flat plane inclined at a given angle with respect to the axis line.

The slope 68 is disposed such that it faces the four pistons 32 a to 32 d in the space 44 in the first housing 26. The slope 68 has a top portion 70 that is closest to the cover member 38 (arrow B direction) and a bottom portion 72 that is closest to the driving unit 12 (arrow A direction), the top portion 70 and the bottom portion 72 being connected to form the flat plane.

The rotating body 30 rotates in the space 44 in the first housing 26 under the driving action of the driving source 18, in a given direction and at a given rotating speed together with the driving shaft 24.

Each of the pistons 32 a to 32 d has a rod portion 74 having a substantially constant diameter and a head portion 76 connected to the other end of the rod portion 74. The pistons 32 a to 32 d are accommodated respectively in the boosting chambers 48 of the second housing 28 in such a manner that they can move along the axial direction (arrow A, B direction). One end of each rod portion 74 has a substantially hemispherical shape and can abut on the slope 68 of the rotating body 30, and is movably supported by the rod cover 50 that closes one end of the boosting chamber 48.

The head portion 76 has a circular cross section and is coupled coaxially to the other end of the rod portion 74 by a tightening bolt 78. The head portion 76 is in sliding contact with the inner circumferential surface of the boosting chamber 48 via a wear ring 80 and a piston packing 82 disposed on its outer circumferential surface.

For each of the pistons 32 a to 32 d, a return spring 84 is interposed between the head portion 76 and the other end of the boosting chamber 48, with the resilient force of the return spring 84 being urged constantly to the driving unit 12 side (arrow A direction). Consequently, one end of the rod portion 74 of each of the pistons 32 a to 32 d protrudes from the second housing 28 into the first housing 26 (arrow A direction) by a given length and abuts on the slope 68 of the rotating body 30.

As shown in FIG. 6, in each first valve chamber 54 in the second housing 28, the intake check valve 34 is disposed in such a manner that it can move along the axial direction (arrow A, B direction). The intake check valve 34 has a valve portion 86 having an enlarged diameter on the cover member 38 side (arrow B direction). A first spring (spring) 88 is interposed between the valve portion 86 of the intake check valve 34 and one end of the first valve chamber 54, where the resilient force thereof presses the intake check valve 34 to the cover member 38 side so that the valve portion 86 abuts on the first plug 60. In this way, the communicating hole 58 of the first plug 60 is closed along the valve portion 86.

The exhaust check valves 36 are formed in substantially the same shape as the intake check valves 34, and are arranged in pairs with the intake check valves 34. Each exhaust check valve 36 is disposed to be movable along the axial direction (arrow A, B direction) in the second valve chamber 56 in the second housing 28, and has a valve portion 90 with an enlarged diameter formed on the driving unit 12 side (arrow A direction). That is, the exhaust check valve 36 is disposed such that its valve portion 90 is alternated with the valve portion 86 of the intake check valve 34 along the axial direction.

A second spring (spring) 92 is interposed between the valve portion 90 of the exhaust check valve 36 and the second plug 62. The exhaust check valve 36 is pressed by its resilient force to the driving unit 12 side (arrow A direction) so that the valve portion 90 abuts on the border of the boosting chamber 48, so as to cut off the communication between the boosting chamber 48 and the second valve chamber 56.

The cover member 38 has a rectangular cross section that is substantially the same as the cross sections of the first and second housings 26, 28, for example, and it has four insertion holes 94 formed at its four corners, into which the coupling bolts 42 are inserted.

Thus, the four coupling bolts 42 are inserted in the insertion holes 94 of the cover member 38 and the through holes 40 a, 40 b of the first and second housings 26, 28, and then engaged in the threaded holes 20 of the casing 16. In this manner, the cover member 38 is coupled to the other end of the second housing 28, and the first and second housings 26, 28 and the casing 16 are coupled in a straight line along the axial direction.

A supply port 96 into which the pressure fluid is supplied is formed in an exterior surface of the cover member 38. The supply port 96 opens in the exterior surface lying in the same direction as the output port 64 of the second housing 28, and piping (not shown) is connected to the supply port 96.

As shown in FIG. 9, the supply port 96 communicates with two supply passages 98 a, 98 b that extend in a direction orthogonal to the axis line of the cover member 38. One supply passage 98 a extending in a vertical direction and the other supply passage 98 b extending in a horizontal direction intersect each other to form substantially a cross shape, and communicate respectively with the four first valve chambers 54 through the communicating holes 58 of the first plugs 60 (see FIG. 6).

In other words, the two supply passages 98 a, 98 b communicate with each other and respectively with the first valve chambers 54 in the vicinities of both their ends, so that the four first valve chambers 54 communicate with each other.

Thus, the pressure fluid supplied from the supply port 96 is supplied through the supply passages 98 a, 98 b into the first valve chambers 54 from the communicating holes 58, and presses the intake check valves 34 to enter into the boosting chambers 48.

The boosting device 10 according to the embodiment of the present invention is basically configured as described above. Next, its operations and functions and effects will be explained.

First, the pressure fluid is supplied into the supply port 96 from a pressure fluid supply source (not shown), and then the pressure fluid flows into the communicating holes 58 of the first plugs 60 through the two supply passages 98 a, 98 b, respectively. Then, the pressure fluid pushes the intake check valves 34 to the driving unit 12 side (arrow A direction), so that the intake check valves 34 move against the resilient forces of the first springs 88 to allow the pressure fluid to go into the boosting chambers 48 through the four first valve chambers 54.

At the same time, the driving source 18 of the driving unit 12 is energized, whereby the driving shaft 24 rotates and the rotating body 30 rotates in a given direction. As a result, the pistons 32 a to 32 d abutting on the slope 68 of the rotating body 30 are pushed in the axial direction (arrow A, B direction) and the pistons 32 a to 32 d start moving.

At this time, the pistons 32 a to 32 d are always urged by the resilient forces of the return springs 84 in the axial direction to the rotating body 30 side (arrow A direction), so that their rod portions 74 keep abutting on the slope 68. Accordingly, while a piston (32 a to 32 d) is abutting on the bottom portion 72 of the slope 68, the piston (32 a to 32 d) is on the driving unit 12 side (arrow A direction). On the other hand, when abutting on the top portion 70, the piston (32 a to 32 d) is on the cover member 38 side (arrow B direction).

Thus, in the state shown in FIG. 4, for example, the piston 32 a is pressed by the top portion 70 of the rotating body 30 to the cover member 38 side (arrow B direction) against the resilient force of the return spring 84, and so its head portion 76 compresses and boosts the pressure fluid in the boosting chamber 48. On the other hand, since the piston 32 c faces and abuts on the bottom portion 72 of the rotating body 30, it is pressed by the resilient force of the return spring 84 to move to the position closest to the driving unit 12 (arrow A direction).

Further, since the pistons 32 b, 32 d are abutting on the slope 68 in a middle portion between the top portion 70 and the bottom portion 72, they are in a middle portion between the positions of the pistons 32 a and 32 c described above.

In this way, as the rotating body 30 rotates, the pistons 32 a to 32 d abut on the slope 68 in continuously varying positions from the top portion 70 to bottom portion 72, so that the pistons 32 a to 32 d reciprocate along the axial direction in a sequential and continuous manner along the circumferential direction. Thus, every time they are moved to the cover member 38 side, they compress and boost the pressure fluid introduced into the boosting chambers 48. In other words, the pistons 32 a to 32 d continuously abut on, and are pressed by, the slope 68 of the rotating body 30 that is inclined with respect to the axis line, and so they reciprocate along the axial direction as the slope 68 rotates.

Then, the pressure fluid compressed under the action of movements of the pistons 32 a to 32 d flows from the boosting chambers 48 into the second valve chambers 56, and the pressure fluid that has been boosted to a given pressure presses opens the exhaust check valves 36 against the resilient forces of the second springs 92.

As the exhaust check valves 36 move to the cover member 38 side (arrow B direction), the second valve chambers 56 and the discharge passages 66 a, 66 b communicate with each other and allow the boosted pressure fluid to discharge from the output port 64 through the discharge passages 66 a, 66 b. The boosted pressure fluid is sent to an accumulator tank and stored therein, for example, and supplied from the accumulator tank to actuators etc. and used.

That is, the four pistons 32 a to 32 d axially move sequentially and continuously as the rotating body 30 rotates, to thereby compress the pressure fluid in the boosting chambers 48 sequentially. Meanwhile, exhaust check valves 36 of boosting chambers 48 that have reached a given pressure are opened sequentially, allowing the pressure fluid to be discharged to the outside from the output port 64.

As described so far, the boosting device 10 of the embodiment includes the driving unit 12 that are driven under the action of energization, and the boosting mechanism 14 coupled to the driving unit 12 and capable of boosting and delivering the pressure fluid. The boosting mechanism 14 includes the rotating body 30 accommodated in the first housing 26, the four pistons 32 a to 32 d that are accommodated in the second housing 28 and axially movable, the exhaust check valves 36 and the four pairs of intake check valves 34 that open and close as the pistons 32 a to 32 d move, and the cover member 38 that closes an end of the second housing 28.

The rotating body 30 is rotated under the driving action of the driving unit 12, and its slope 68 causes the pistons 32 a to 32 d to reciprocate in the axial direction sequentially and continuously, to thereby compress and boost the pressure fluid supplied into the boosting chambers 48 that accommodate the pistons 32 a to 32 d.

As a result, the boosting device 10 capable of compressing and boosting the pressure fluid can be made smaller in size and lighter in weight, by employing the configuration in which the four pistons 32 a to 32 d are arranged in the circumferential direction and the rotating body 30 having the slope 68 is rotated under the driving action of the driving unit 12 to axially move the pistons 32 a to 32 d continuously.

In other words, because the four pistons 32 a to 32 d are disposed within the outer circumferential surface of the rotating body 30 in the radial direction, the boosting device 10 can be sized small, without being sized larger outward in the radial direction.

Furthermore, because an end of the rod portion 74 of each of the pistons 32 a to 32 d is formed substantially in a semispherical shape, it can always abut on the inclined slope 68 reliably and stably even when the rotating body 30 rotates, enabling the pistons 32 a to 32 d to move stably in the axial direction.

Moreover, the rotating body 30 having the slope 68 at the end that faces the pistons 32 a to 32 d is rotated under the driving action of the driving unit 12, whereby the pistons 32 a to 32 d arranged at intervals in the circumferential direction can be pressed in turn and moved in the axial direction. Accordingly, the pistons 32 a to 32 d can compress and boost the pressure fluid in turn and in succession.

The description of the boosting device 10 above has illustrated the boosting mechanism 14 that includes the four pistons 32 a to 32 d and the four pairs of intake check valves 34 and exhaust check valves 36, but the mechanism is not limited to this configuration. The number of components are not particularly limited as long as the number of pistons 32 a to 32 d and the number of intake check valves 34 and exhaust check valves 36 are determined to form pairs.

The boosting device of the present invention is not limited to the embodiment described above, and various configurations are of course possible without departing from the essence and gist of the present invention. 

1. A boosting device that includes a body having a supply port and an output port and that is configured to increase a pressure of a pressure fluid supplied from the supply port and to output the boosted pressure fluid from the output port, the boosting device comprising: a driving source that is provided in the body and that is rotationally driven under an action of energization; a rotating body coupled to a rotating shaft of the driving source and having a slope that is inclined with respect to an axis line of the rotating shaft; and a plurality of pistons disposed to be movable in an axial direction with respect to boosting chambers in the body and each having an end that abuts on the slope, wherein the plurality of pistons are sequentially urged in the axial direction by the slope under an action of rotation of the rotating body, so as to compress and boost the pressure fluid in the boosting chambers.
 2. The boosting device according to claim 1, wherein the plurality of pistons are arranged along a circumferential direction on a circumference about an axis line of the body, and disposed inside an outer circumferential surface of the rotating body in a radial direction.
 3. The boosting device according to claim 1, wherein an end of each of the pistons that abuts on the rotating body is formed substantially in a hemispherical shape.
 4. The boosting device according to claim 1, wherein the boosting chambers are each provided with a switching mechanism for establishing communication with the supply port when the pressure fluid is supplied and establishing communication with the output port when the pressure fluid is discharged.
 5. The boosting device according to claim 4, wherein the switching mechanism includes: a first switching valve that opens only when the pressure fluid is supplied; and a second switching valve that opens only when the pressure fluid is discharged.
 6. The boosting device according to claim 5, wherein each of the first and second switching valves rests and closes under a resilient action of a spring, and opens under a pressing action by the pressure fluid.
 7. The boosting device according to claim 2, wherein an end of each of the pistons that abuts on the rotating body is formed substantially in a hemispherical shape. 